a,27,3x4,6+96,4x27,3-27,3=27,3x(4,6+96,4-1)=27,3x100=2730
b,87,4x12,74+74,52x43,7=43,7x2x12,74+74,52x43,7=43,7x25,48+74,52x43,7=43,7x(25,48+74,52)=43,7x100 =4370
c,0,1+0,3+0,5+...................+3,7+3,9=(0,1+3,9)+(0,3+3,7)+................(1,9+2,1)=4+4+.............+4(10 số 4)=4x10=40
Tick nha